Linux Distros Unpatched Vulnerability : CVE-2026-86818

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(345871);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/16");

  script_cve_id("CVE-2026-86818");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-86818");

  script_set_attribute(attribute:"synopsis", value:
"The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be
patched.");
  script_set_attribute(attribute:"description", value:
"The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied
patch available.

  - fast-uri is a dependency-free RFC 3986 URI parser for Node.js, used by Fastify and ajv, that added a
    mailto scheme parser in version 4.1.3. In versions 4.1.3 and 4.1.4, the mailto parser compares each query
    field name to the reserved names to, subject, and body while the name is still percent-encoded, and
    decodes it only when storing it as a generic header, so a percent-encoded spelling of a reserved field
    name is not recognized as that field at parse time but is re-emitted as the literal field name when the
    parsed URI is serialized. An application that validates, logs, or displays the recipient list from the
    first parse and then serializes the URI and sends it can silently gain an attacker-chosen recipient, and
    the subject and body fields can be smuggled across the same roundtrip. The issue is fixed in fast-uri
    4.1.5, and users should upgrade to 4.1.5 or later. As a workaround, do not act on a mailto URI that fast-
    uri has re-serialized without first decoding and re-validating its recipient, subject, and body fields.
    (CVE-2026-86818)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/cve-2026-86818");
  script_set_attribute(attribute:"solution", value:
"There is no known solution at this time.");
  script_set_attribute(attribute:"agent", value:"unix");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:P/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-86818");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_set_attribute(attribute:"vendor_unpatched", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/09/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/15");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:centos:centos:8");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:8");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:9");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:aspnetcore-runtime-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:aspnetcore-runtime-dbg-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:aspnetcore-targeting-pack-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:cockpit-image-builder");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:dotnet");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:dotnet-apphost-pack-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:dotnet-host");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:dotnet-hostfxr-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:dotnet-runtime-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:dotnet-runtime-dbg-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:dotnet-sdk-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:dotnet-sdk-8.0-source-built-artifacts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:dotnet-sdk-dbg-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:dotnet-targeting-pack-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:dotnet-templates-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:dotnet8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:grafana");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:grafana-pcp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:grafana-selinux");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:linux-sgx");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:netstandard-targeting-pack-2.1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:sgx-common");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:sgx-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:sgx-mpa");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:sgx-pccs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:sgx-pccs-admin");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:sgx-pckid-tool");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:tdx-qgs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:aspnetcore-runtime-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:aspnetcore-runtime-dbg-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:aspnetcore-targeting-pack-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:cockpit-image-builder");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:dotnet");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:dotnet-apphost-pack-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:dotnet-host");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:dotnet-hostfxr-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:dotnet-runtime-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:dotnet-runtime-dbg-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:dotnet-sdk-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:dotnet-sdk-8.0-source-built-artifacts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:dotnet-sdk-dbg-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:dotnet-targeting-pack-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:dotnet-templates-8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:dotnet8.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:grafana");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:grafana-pcp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:grafana-selinux");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:linux-sgx");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:netstandard-targeting-pack-2.1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:sgx-common");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:sgx-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:sgx-mpa");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:sgx-pccs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:sgx-pccs-admin");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:sgx-pckid-tool");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:tdx-qgs");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl", "set_linux_os_id.nasl");
  script_require_keys("Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched", "Host/OS/identifier");
  script_require_ports("Host/OS/CentOS Linux-8", "Host/OS/Red Hat Enterprise Linux-10", "Host/OS/Red Hat Enterprise Linux-8", "Host/OS/Red Hat Enterprise Linux-9");

  exit(0);
}

if (!get_kb_item("global_settings/vendor_unpatched")) exit(0, "Unpatched Vulnerabilities Detection not active.");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (empty_or_null(get_one_kb_item("Host/CentOS/rpm-list")) && empty_or_null(get_one_kb_item("Host/RedHat/rpm-list"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Red Hat Enterprise Linux-10": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "10",
        "pkgs": [
          {"reference": "aspnetcore-runtime-8.0"},
          {"reference": "aspnetcore-runtime-dbg-8.0"},
          {"reference": "aspnetcore-targeting-pack-8.0"},
          {"reference": "cockpit-image-builder"},
          {"reference": "dotnet-apphost-pack-8.0"},
          {"reference": "dotnet-hostfxr-8.0"},
          {"reference": "dotnet-runtime-8.0"},
          {"reference": "dotnet-runtime-dbg-8.0"},
          {"reference": "dotnet-sdk-8.0"},
          {"reference": "dotnet-sdk-8.0-source-built-artifacts"},
          {"reference": "dotnet-sdk-dbg-8.0"},
          {"reference": "dotnet-targeting-pack-8.0"},
          {"reference": "dotnet-templates-8.0"},
          {"reference": "dotnet8.0"},
          {"reference": "grafana"},
          {"reference": "grafana-pcp"},
          {"reference": "grafana-selinux"},
          {"reference": "linux-sgx"},
          {"reference": "sgx-common"},
          {"reference": "sgx-libs"},
          {"reference": "sgx-mpa"},
          {"reference": "sgx-pccs"},
          {"reference": "sgx-pccs-admin"},
          {"reference": "sgx-pckid-tool"},
          {"reference": "tdx-qgs"}
        ]
      }
    ]
  },
  "CentOS Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "aspnetcore-runtime-8.0"},
          {"reference": "aspnetcore-runtime-dbg-8.0"},
          {"reference": "aspnetcore-targeting-pack-8.0"},
          {"reference": "dotnet"},
          {"reference": "dotnet-apphost-pack-8.0"},
          {"reference": "dotnet-host"},
          {"reference": "dotnet-hostfxr-8.0"},
          {"reference": "dotnet-runtime-8.0"},
          {"reference": "dotnet-runtime-dbg-8.0"},
          {"reference": "dotnet-sdk-8.0"},
          {"reference": "dotnet-sdk-8.0-source-built-artifacts"},
          {"reference": "dotnet-sdk-dbg-8.0"},
          {"reference": "dotnet-targeting-pack-8.0"},
          {"reference": "dotnet-templates-8.0"},
          {"reference": "dotnet8.0"},
          {"reference": "netstandard-targeting-pack-2.1"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "aspnetcore-runtime-8.0"},
          {"reference": "aspnetcore-runtime-dbg-8.0"},
          {"reference": "aspnetcore-targeting-pack-8.0"},
          {"reference": "dotnet"},
          {"reference": "dotnet-apphost-pack-8.0"},
          {"reference": "dotnet-host"},
          {"reference": "dotnet-hostfxr-8.0"},
          {"reference": "dotnet-runtime-8.0"},
          {"reference": "dotnet-runtime-dbg-8.0"},
          {"reference": "dotnet-sdk-8.0"},
          {"reference": "dotnet-sdk-8.0-source-built-artifacts"},
          {"reference": "dotnet-sdk-dbg-8.0"},
          {"reference": "dotnet-targeting-pack-8.0"},
          {"reference": "dotnet-templates-8.0"},
          {"reference": "dotnet8.0"},
          {"reference": "netstandard-targeting-pack-2.1"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-9": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "9",
        "pkgs": [
          {"reference": "aspnetcore-runtime-8.0"},
          {"reference": "aspnetcore-runtime-dbg-8.0"},
          {"reference": "aspnetcore-targeting-pack-8.0"},
          {"reference": "dotnet-apphost-pack-8.0"},
          {"reference": "dotnet-host"},
          {"reference": "dotnet-hostfxr-8.0"},
          {"reference": "dotnet-runtime-8.0"},
          {"reference": "dotnet-runtime-dbg-8.0"},
          {"reference": "dotnet-sdk-8.0"},
          {"reference": "dotnet-sdk-8.0-source-built-artifacts"},
          {"reference": "dotnet-sdk-dbg-8.0"},
          {"reference": "dotnet-targeting-pack-8.0"},
          {"reference": "dotnet-templates-8.0"},
          {"reference": "dotnet8.0"},
          {"reference": "linux-sgx"},
          {"reference": "netstandard-targeting-pack-2.1"},
          {"reference": "sgx-common"},
          {"reference": "sgx-libs"},
          {"reference": "sgx-mpa"},
          {"reference": "sgx-pccs"},
          {"reference": "sgx-pccs-admin"},
          {"reference": "sgx-pckid-tool"},
          {"reference": "tdx-qgs"}
        ]
      }
    ]
  }
};

var distro_constraints_values = linux_unpatched::get_distro_constraints(distro_constraints_arr:distro_constraints_array);
if (empty_or_null(distro_constraints_values)) audit(AUDIT_HOST_NOT, 'affected');

var third_party_support = get_kb_item('Host/OS/extended-third-party');
if (!empty_or_null(third_party_support)) {
    var third_party_vendors = distro_constraints_values['third_party'];
    if (!empty_or_null(third_party_vendors)) {
        var vendor;
        foreach vendor (third_party_vendors) {
            if (vendor == third_party_support) exit(0, 'A third party management patch is available for this vulnerability from ' + vendor + '.\n');
        }
    }
}

var report = linux_unpatched::check_unpatched_constraints(distro_constraints_values:distro_constraints_values);

if (!empty_or_null(report))
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}